Using somatic cell hybridization techniques, monoclonal antibodies are being prepared against antigens associated with human acute lymphoblastic leukemia. Studies are proposed to examine the pharmacokinetics and toxicity of these reagents after intravenous infusion. Methods are being sought to utilize or to prevent modulation of antigens from the surface of ALL cells. Monoclonal antibodies are being used to eliminate leukemic cells from bone marrow before antigenic modulation occcurs, facilitating autologous marrow transplantation.